At present classification of liquid mixtures in accordance with molecular weight is effected by means of commercial apparatus comprising a plurality of tubular classifiers connected in series to form sections which are parallel connected to a manifold and form a unit of the apparatus. Each tubular classifier comprises one tubular filtering element.
However, during operation of such apparatus, a precipitate is formed on the filtering surface of the tubular element during classification of liquid mixture. This results in a decrease in the efficiently of classification of the liquid mixture and a reduction of the throughput and/or output capacity of the apparatus, so that the apparatus should be stopped at regular intervals for cleaning of the filtering elements.
British patent specification No. 1256491 discloses an apparatus comprising a plurality of tubular classifiers connected in series to one another and which are formed into sections which are parallel connected to a manifold and form a unit of the apparatus. A hollows casing of each tubular classifier accommodates a plurality of filtering elements extending in parallel with the longitudinal axis of the tubular classifier and connected in series to one another. For removal of filtrate from the inner space of the tubular classifier, there is provided a pipe. End plates with pipes for admission of liquid mixture and removal of concentrate, respectively, are provided at the extremities of the hollow casing.
However, during the operation of the apparatus, a precipitate is deposited in the passages of the end plates interconnecting the series-connected tubular filtering elements. The precipitate is also deposited on the filtering surface of the filtering elements. The precipitates are formed as a result of laminary flow of the stream of liquid mixture in the tubular filtering elements.
The formation of precipitates lowers the efficiency of classification of a liquid mixture and reduces the throughput and/or output capacity of the apparatus. To remove the precipitate from the tubular filtering elements and passages of the end plates of the tubular classifiers, considerable time and skilled maintenance personnel are needed.
In view of the development and growth of a number of industries where it is required to classify liquid mixtures in accordance with molecular weight, and considering the great need to isolate valuable components from waste liquor, and in enriching starting products, the demand for such apparatus is constantly growing.
However, the prior art apparatus for classifying liquid mixture in accordance with molecular weight cannot comply with the evergrowing requirements as to efficiency and overall capacity.
Therefore, there is a long-felt need to improve the prior art apparatus for classifying liquid mixture in accordance with molecular weight, such as waste liquor containing silver salts, for concentration of enzyme preparations and classification of washing liquor containing soaps and fats.